1. Field of the Invention
The invention generally relates to the deletion of data from a database. In particular, the invention relates to the automatic deletion of expired data in a distributed database system.
2. Background
As used herein the term “record expiry” refers to a system-initiated deletion of a database record. Database records may be set to expire for any number of reasons. For example, the value or relevance of some information decreases over time. Additionally, expiry may be used to remove older data from a system to free up resources to make room for newer data.
Various approaches are known for automatically determining when a record in a database has expired and then deleting the record accordingly. By necessity, every approach adds some level of complexity to a database system and consumes some resources of the system. In a distributed database system in which multiple copies of the same record exist in different storage locations, record expiry becomes an even more complex task as the expiration of a record must be carried out in a manner that ensures that different versions of the same record can be properly sequenced after the expiration has occurred. Furthermore, the expiration of a record in a distributed database system consumes even more resources as database operations impacting one copy of a record must be propagated to remotely-stored copies of the same record.
What is needed then is a technique that reduces the complexity and resource consumption associated with performing record expiry in a distributed database system.